There are a number of devices on the market for self-administration of drugs where the drug is stored in powder form in a medicament container. This is due to the fact that many drugs, when mixed with a diluent, tend to degenerate if stored. There is thus a growing market for so called multi-chamber medicament containers, i.e. containers having at least two chambers, where at least one chamber contains the medicament in powder form, i.e. the medicament agent, and one chamber contains the diluent agent with which the medicament is to be mixed prior to delivery.
For many devices the mixing of the medicament and the diluent is performed by manually operating a medicament delivery device such as an injection device.
One such device is disclosed in WO2009100550 where a proximal housing part is turned in relation to a distal housing part whereby the first or proximal housing part having a multi-chamber medicament container is engaged and moved into the distal housing part. This, in turn, causes a plunger rod via a first piston-like member to urge the diluent agent in one of the chambers into a second chamber through channels in the container, wherein the channels fluidly interconnect the two chambers. The medicament powder and the diluent agent are mixed into a reconstituted medicament.
To activate the delivery of the medicament, i.e. to inject the medicament, an activation member, in the form of a push button, at one end of the injector is activated. In order to prevent an activation of the device before the mixing step or process is completed, the actuation member or push button at the distal end of the device is locked by a locking member that blocks the axial movement of the push-button relative to the housing, i.e. the push-button is hindered from being pressed. At the end of the mixing sequence, the locking member is activated and moved out of its locking position. After performed mixing, a dose delivery is thus activated by manually operating the actuation member.